1. Field of the Invention
The present invention is directed to a protective tarpaulin useful in protecting targets from multiple weapon systems. More specifically, the present invention is directed to a protective tarpaulin which shields a military target against surveillance, identification lock-on systems and high energy destruction weapons.
2. Background of the Prior Art
Surface military targets, including ground vehicles and installations, are susceptible to surveillance, identification and lock-on as well as destruction by high energy weapons. Thus, surface military targets are susceptible and vulnerable to multiple weapon systems in that these weapon systems provide surveillance, identification and lock-on as well as high energy weapon capability. That is, multiple weapon systems both search out and destroy the target to which they are aimed. Moreover, the surveillance, identification and missile lock-on capability of multiple weapon systems operate over multiple bands of the electromagnetic spectrum.
To better understand the dangers to surface military targets posed by multiple weapon systems it must be understood that these systems are provided with three capabilities: passive surveillance capability, active surveillance capability and high energy weapon capability. These threat system capabilities, and the danger they pose to military targets, are considered hereinafter.
Those skilled in the art are aware that passive surveillance systems, provided in multiple weapon systems, include passive detection, recognition and identification utilizing electro-optical systems operating in the visual, radio frequency and infrared wavelength bands. Visual systems operate in the 0.4 to 0.7 micrometer portion of the electromagnetic spectrum. These systems rely on the visual, that is, that which is recognizable by the human eye. In addition, optical augmentation systems, which range from hand-held binoculars to video display terminals with zoom-in capability, are provided in multiple weapon systems. Detection mechanisms employed in visual systems are accomplished through color and/or brightness contrast.
Passive systems which operate in the infrared wavelength bands, the 0.8 to 14 micrometer portion of the electromagnetic spectrum, which includes the solar band, the high temperature band and the low temperature band, operate by homing-in on the contrast between the target and its background. Such systems as the forward looking infrared systems on aircraft and helicopters, infrared missile seekers on air-to-surface and surface-to-surface missiles, electro-optical/infrared surveillance/warning systems on land or air combat vehicles and electro-optical/infrared sensors in space are among the many currently used infrared passive systems utilized to identify military targets.
Active systems utilized by multiple weapon systems include both active optronic and radar systems. Optronic systems operate either as laser rangefinders or coupled laser/electro-optical rangefinders/missile lock-on systems. These systems generally rely on the retroreflection of surface materials for detection, recognition, identification and lock-on. These systems are tuneable and operate in both the visual and infrared portions of the electromagnetic spectrum.
Radar systems, another class of active systems, operate between decametric waves (high frequency) to and including millimetric waves (extremely high frequency) portions of the electromagnetic spectrum. Radar systems are designed to emit a pulse of electromagnetic energy and rely on the echo return of the reflected pulse to detect, recognize, classify and identify the target.
Finally, high energy weapons utilized in multiple weapon systems, to which military targets are vulnerable, are either high energy lasers or nuclear detonating weapons.
The development, in recent years, of multiple weapon systems, which incorporate passive surveillance systems, active surveillance systems and high energy weapons, necessitates an appropriate response to protect military targets which these multiple weapon systems are designed to destroy. That is, there is a need in the art to develop a single countermeasure to protect ground military targets against all the potential threats posed by the multiple weapon systems discussed above.
Tarpaulins are traditionally utilized in the covering of various stationary objects. When utilized to cover military-related devices, such as buildings, weapons, vehicles and the like, they are employed not only to protect the covered object but may also be used to camouflage it. It may be argued, however, that coverings for military targets used in the prior art were not tarpaulins in the traditional sense. That is, the camouflage systems of the prior art, used in military applications, have not been characterized by the mobility associated in the prior art with tarpaulins.
Among the camouflage systems utilized in the prior art, mention should be made of the system of U.S. Pat. Nos. 4,473,826 and 4,495,239. These patents disclose a covering utilized to camouflage military targets. The target covered by the camouflage system of these patents has the common characteristic of generating heat. The camouflage system of the '826 and '239 patents protect against detection by sensors responsive to radar, infrared, visible and ultraviolet electromagnetic frequencies. The covering of these patents encompasses a camouflage netting provided with an infrared reflecting layer and an internal forced air heat redistribution system.
U.S. Pat. No. 4,609,034 describes another infrared camouflage system where air is forced through camouflage panels so that infrared emissions through the panels from a covered heat source are minimized. A sensor controls the air flow rate through the panels by responding to ambient infrared conditions and emissions from the panel.
U.S. Pat. Nos. 3,349,396 and 3,349,397 are both directed to a flexible radiation attenuator. This attenuation is provided by a flexible material, which covers military vehicles, that attenuates radiation in the radar frequency range.
These systems, although having in common the purpose of camouflaging surface targets from military weapons, do not provide against detection, identification and lock-on capability of a target, provided by passive and active systems, in combination with protection against the devastating effect of a high energy weapon. Moreover, none of these systems are lightweight, highly mobile devices of the type that are normally categorized as tarpaulins. Thus, there is a recognized need in the art to develop such a tarpaulin as a military protective system effective against multiple weapon systems which is, at the same time, flexible, mobile and quickly assemblable for use to cover and protect military targets.